What do you wear under your gi? Having issues with arousal.

What do you guys prefer wearing under your gi? I've found that boxers or shorts are far too loose, but I don't like the restrictions placed on my movement by tighter briefs of athletic supporters. I prefer a full range of motion if possible.



I've started going commando against the advice of my sensei, but certain movements create friction "down there" in a way that my classmates may not be comfortable with.



Any advice would be appreciated.